Power transmission



13, 1951 F. T. HARRINGTON ETAL. 2,544,990

POWER TRANSMISSION 5 Sheets-Sheet 1 Filed Jan. 4, 1947 r li'ritllfiillll. :1. i llrlllllllilll w 4F M IJ II INVENTORS LESLIE W. HAISEN GORDON R. ELLIOTT FERRIS T. HARRINGTON JOSEPH A MARTIN ATTORN EY 4 m .1 2 w w 4 I 3 4 w fi 4 2 w o 6 8 4 4 4/ 4 w n 9 3 March 13, 1951 F. T. HARRINGTON ET AL 2,544,990

POWER TRANSMISSION 5 SheetS-Sheet Z Filed Jan. 4, 1947 FIG. 5

INVENTORS- LESLIE W. HAISEN GORDON R. ELLIOTT FERRIS T. HARRINGTON FIG.4

JOSEPH A. MARTIN BY 7 A ATTORN EY March 13, 1951 F. T. HARRINGTON ETAL 2,544,990

POWER TRANSMISSION Filed Jan. 4, 1947 5 Sheets-Sheet 4 F I G. I4

INVENTORS LESLIE WIHAISEN GORDON R. ELLIOTT FERRIS T. HARRINGTON JOSEPH A. MARTIN FIG. I2

AT'TORN EY March 13, 1951 Filed Jan. 4, 1947 F. 'r. HARRINGTON YETAL POWER mmsmssrou 5 Sheets-Sheet 5 INVENTORS LESLIE W. HAISEN GORDON R. ELLIOTT FERRIS T. HARRINGTON 6 BY JOSEPH A.MART|N ATTO RN EY Patented Mar. 13, 1951 sears NT POWER TRANSMISSION Ferris T. Harrington and JoseplnA; Martin Detroit; GOPGOIIfr R. Elliottp-Eerndale, and Leslie Haisen Royal Oak, Mich ,assignors; to 7.- yickersjIncorporated, Detroit, Mich, a 'corporation"of fMichi'gan UNITED o ll This invention relates: to power -transmissions in general, 'butimore-particularlyto auxiliary,hy

:adraulic z'plower-transmissipns such -as-thoseemployed-onfarxh tractorsgand roadmachinery.

.- In .the early .days'of :farm tractorgthesole put-'; o;-;pose of:the tractorw-as to replace the horse or ;jother beastsqof burden ingsupplyingmotor power.

. The-old: horse-drawnagang-plowcwas merely-couled to,thewtractomandzthemanipulation of the zcoupled toithe tractor-so that the; tractor operator i was ableto ocont-rolnthe plow tpersonally, :but even -As theinumberof plowsicapable of being hauled or the size ofvthmbulldozer =b1ade' used-5 increased zwith :the increase 7 in :tractor power; itheumanual control of: accessories:became-more difficult-{rim a-result,: it ib'ecame necessary to employ; the. trac-vl '1 i torzpoweri foractuatingthe-accessoriestalso. ,The

. jsimplest andmost natural way for transmitting tractorpower to any point :oonntheitractor frame for driving an accessory was by hydraulicpower.

Thereforeot-he generahobject; ofrqthis invention:

to provide a :hydraulic'transmission drivenby a: tractor engine for operating-[auxiliaryequipment: or; power accessories as attachmentsrto the v-. main machine.

VAI standard hydraulic .transmission employs pump," tank, and, motor elements controlled Joy a directional zvalve in; the conduits; connectingothe elements. -.-Each accessory;hasits own independ- -rent--load. requirements-depending upon itsj,-size \and the Work-to be-taecomplished- ;.Consequent1y,-

a common work cylinder or motor is seldom adaptable:to allgload.conditions.1: Therefore; it is .estandard; practice to1furnish.teach: accessory o equipped with a ;-special, hydraulic motor. for its particular. requirements, and thensupply it with pressure fluid-o from a common source of: hydraulic p0,wer.

Another :object ofathis invention is toaprovide a hydraulic power :device ncomprising pump, vtank, and-xvalve elements ion-operating.- a motor.

' Such, a power; device mustberdesigned vinrsiich a mannerl asto,facilitateumounting the device on the tractor. Sinceithespace availablesfor. addi- -tional, equipment is limited, the :yarious v elernents o-xrcomprisingi thedevicemnst be small andscompact lowsrwerejstillrhandled manuallylby -the p1ow. op+.;;

10:;punips capacity. I consfiquentlyoltheerator.v '1 Subsequently; aspecialoplow:wasqclosely a ,tractor: owner, if he .has .not,alreadyl,doneo templates eq iipping. his tractor v with various v ..types oftpoweraaccessories-MIn inany casese one accessory-may require-two. ormorehy "ulirggnotimes desirable to operate tWOaOithElglOELd evices or. motorssimultanewsly or, at least provide "for consecutive.operation."QTQ acc mpIi his, -iti yvas a cnecessarytop vi e ul e a ves,f athenow pack.

Anotherobject-ofltheninvention is to provide a =-=mult p1e1va v .ba ktedeni dz embIeci as an-integral part of.thelpower paclg;assemblyand capable of independently controlling each niotor 2a. orpoweraccessory.

Further -it-is anobject-to so arrangelthe unit ithat. the main-assemblyjmayl beivbi ilt upgwith-yarmious numbers.-of/control-yalves, anyof which may 1 be removedon added interchangeably;usinggihe same basic parts.

r Inorder; to consolidatedthe. elements ,intoga uni- -.taryiassemblylto conserve space andimaterialaand v :producetan economicalnnit;the-varimselernents i 1- havetbeen designed ato servezmore than cnemnrpo er-J 1 examp e gdirc t q a yval ejhcasin al-solserves-ras an; zintegral part of the pump .1 Pasezisages are providedirinothatabodvinlplaeeg gexter- .na'Lconduits such; as. copper tubesiconnectinguthe pumpand valve elements.

Therefore, another object ofthepresent-invention is to provide an assembly; of elements into a -3unitary powerpack-wherein the-"individual ele- "-*ments-;frequentlyserve combinationfunctions in 5 operation.

For economical reasons, the V passages inthe .valve block or body areja'llo f 1a straightform and normally perpendicular ,tooneiof the ;o 1ter suriia.ces,, ot thablock, i. such a ,fdesign eliminates the necessityiof coredpassages, and makesposible a 3 saving by drilling the passages on multiple spindle drills.

Therefore, another object is to design a valve block and housing in which all the passages are straight and perpendicular to one of the surfaces of the block.

In the hydraulic transmission designs employing reservoirs, it is the usual practice to set the pump below the level of the reservoir or if possible to locate the pumps directly in the reservoir below the hydraulic fluid level. In the present design, the pump is enclosed in a drawn metal tank element below the oil level. Further, the pump and valve housing also function as a cover to which the open end tank element is fastened to provide a sealed enclosure for the pump.

Another object of the invention is to provide a power pack in which an open end drawn metal tank element may be assembled on the combination valve and pump housing as a cover and enclose the pump within the tank in a manner to produce a positive head of oil at the pump intake.

A novel relief valve is also a. feature of the design. The valve comprises a drawn metal body provided with a bushing at one end thereof adapted to function internally as a valve seat and externally as an oil seal. The body contains a spring and ball valve and the internal bore functions as the passage to the tank enclosure for discharging fluid.

A novel filter design is employed wherein a semi-rigid tubular shaped screen element is maintained between two end pieces. A coil spring having a coil diameter approximately equal to the internal bore of the tubular screen functions as an internal support therefor and also serves to maintain the end plates and screen in assembled position by spring tension. The mounting end piece of the filter assembly is adapted to be held by the pump head bolts and cover the inlet ports in the head. A baffle plate has been provided and is adapted to be held by the pump head bolts. It has been designed and positioned so as to intercept the normal direction of return flow to the tank. It forms a channel bounded by the pump head housing and baflle to form a passage at right angles to the direction of return flow entering the tank.

Another object was to design cooperative accessories such as relief valves, filters, baflies, etc.

adapted to be assembled into the unitary structure in sucha manner as to produce a highly efficient power pack and an economical structure to build and maintain. Still another object of the invention is to provide a power pack including a pump with a floating pressure head located in the body housing for sealing the rotor and ring with a force varying in proportion to the operating pressure.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings: Figure 1 is a sectional view of a hydraulic power pack embodying a preferred form of the present invention and taken along the line ll of Figure 4.

. Figure 2 is a section on line 2-2 of Figure 1.

FigureB is a view of the fixed pressure head on line 3.-3 of Figure 1.

Figure ,4 is a .section on line 44 of Figure 1. Figure 5 is a section on line 5-5 of Figure 4.

Figure 6 is an end elevation of the bafiie.

Figure 7 is a partial view of the valve block showing the location of the passages therein.

Figure 8 is a section on line 8-8 of Figure '7. Figure 9 is a section on line 9-9 of Figure 7. Figure 10 is a section on line I6|6 of Figure 7. Figure 11 is a section on line ll-H of Figure 12.

Figure 12 is a sectional view of a multiple valve block along the center line of the valves corresponding to line l2l2 of Figure 15.

Figure 13 is a section on line l3l3 of Figure 12.

Figure 14 is a section on line l4-l4 of Figure l2.

Figure 15 is a section on line l5-l5 of Figure 12.

Figure 16 illustrates a hydraulic transmission employing a preferred form of the invention and provided with multiple valves and motors.

The various elements making up the power pack of Figures 1 and 4 include the body I6 housing the valve 12 and pump 14. An open end tank element I6 is fastened to the body [6 by bolts N3 in tapped holes l9 and encloses the baiile 20 and filter 22. A combination air vent and filler cap 24 is mounted on top of the tank 6.

The pump l4 comprises a rotor 26 provided with radial vanes 28 mounted in the cam ring 30 between a fixed pressure head 32 and a floating pressure head 34. The rotor 26 is mounted on the drive shaft 36 and fastened by key 38. The fixed pressure head 32 is provided with armate axial inlet ports 46 and 42 connecting the pump working chamber 44 directly to tank. The floating pressure head 34 is in the form of a radial flange attached to a hub portion 46. The head 34 is adapted to move axially along shaft 36 in the pressure chamber 48 and be maintained in sealing contact with the ring 36 and rotor 26 by means of operating pressure in chamber 48. Outlet ports 50 and 52 in floating head 34 extend directly through the head from the pump working chambers 44 to the pressure chamber 48. Operating pressure fluid is discharged from the working chambers 44 by means of the outlet ports 56 and 52 to the pressure chamber 48 and then to the discharge passage 54 and so on to the directional valve 12.

The pump drive shaft 36 is supported by bearings 56 and 58 and is provided with a key 60 at its outboard end for coupling to a prime mover, which may be the tractor engine, in any convenient manner. An oil seal 64 comprising a cylindrical sealing element 66 located in the guide 68 is extruded radially into sealing contact with shaft 36 as a result of the force of the resilient element 16 in combination with oil pressure communicated through the passage 12 against the end of the seal 66 into sealing contact with shaft 36.

The rotor 26 is provided with radial vane slots 14, the base or inner ends of which are adapted to carry operating pressure communicated from annular grooves 16 and 18 in the side of the rotor 26 for forcing the vanes 28 outward into contact with the cam ring 36 to form the working chambers 44 between the pressure heads 32 and 34. The annular groove I6 communicates with pressure chamber 48 by means of four diagonal passages 86 through floating pressure head 34.

During normal operation, the floating head 34 is maintained in sealing contact with the ring 30 and rotor 26 by means of operating pressure.

During standby or starting conditions, a resilient element such {as spring 82 is employed to "provide aseanng force in the' absence o'fbperating pressure. 1 The "fixed pi'es's'ure head 32 and ring 30 -are-fastenedvtogether and to the body' l El by means "of 'eight 'bolts ll through bolt holes' 83 and 85 respectively.

' Two dowelpins 86 located in: dowel holes -88 in' 'b'ody I are adapted' toi enter a'nd' alig'n dowel holes- 90 and-emf ring SB' ai-ICF dowel holes 92 in fixed pressure head 32. Said dowel holes '9fl I and 9! in'the'cam ringflid are'di'arrietricallyopposed and a'ngularly' displaced. from the major 1 1 diameter aa 'o'f thecam' ellipse by: an "angle-of 45 (see Figure 2).

The function of the "dowels is'to provide :accurate meansfor changing the-relativeiposition of the pump elements when 'the directionof rotation is -reverse'dJ 'When the direction i'of -rotation of the drive shaft 36 is reversedgthe v cam ring-30 and rotor 26 tvith vanes 2B maybe. ro-- tated end for end. In the new-position; the

dowel hole 99- occupies the form position .of

the dowel hole -9 l i and vice versa. 1:In athat case,

"displaced through an angle of -90- to 0ccupythe position BB as" shown in' Figure 2 and the pump elements would be im-position for reversed-rotation.

- dowel hole 96 in the floating pressure-head=-34;-

the major axis AA of the-ellipse wouldhave been A dowel pin 94 in body l 0' is adapted-to enter Dowel 94 maintains the outlet ports 4%] and- 42 of the head 34 mcorrect position relative to the discharge point of the rotor working-chambe'r lfl.

An openend tankelement it is preferably made'of sheet metaiby adratving process. 4 double reverse curved beadorflange-llfi has'been provided for-holding a sealing element l-llil. The

' open endtank element-l6 is' ada'p tedto be closed by thebodyllljactingas a coverthereby positioning the pump I4 and filter- 22 within the-tank enclosure. An air vent 24 is loc'atedin the wall of the' tank I6 for maintaining-atmosphericpresmounted-between two end pieces-104 and 406-, I

sure in the tank.

The filter 22 comprises a' tubularscreen I02 one of which functions as a 'mounting flange HM and 'the oth'eras'an end- Or assembly cap 106. The end cap 106 isprovided vvith a boss' -lll8 adapted tom the insidediameter ofthe tubular screen element ill-2 I as a supporting frame mem her) The mounting 'fiange 'l tl 'is provided-with approximately equal to the bore of thet'ubular asimilar boss I 10 adapted to fit theoppositexend *of the tubular screen.

A coil spring li2-has an outside coil: diameter screen 302. The spring- I [2- is adapted to'be" held at one end by the lips I M on the mounting flange Hi4 a rid'at the other end'by an eye :I [6. formed --fin the end cap 186. Since the spring is under slight tension, it holds the flangeLLlMand-cap lllfi in position .on' thE BIIdIOf .the screen tube Yandplace's the. tubular. screen element 1.02; under .slight compression; 1T0" prevent ..the :..tubular screenillZ: from Collapsingthe coil' spring. .llZ

.=. bears:;against the inner .wall ofthe screen-and acts as a frame. support. to. help :maintain-the screens tubular shape.

.The filter. mounting .fiange 104 isprovidedlvvith I bolt holes for accommodating;the;:;bolts1.34.and

thus fasteninggthe filter to. the pressure 1 head": 32'. Suction fluid fromtthe tank. I6 is drawn through the screen l 12 and ,passes axiallythrough the tubular element and .the; -.-opencenter, mounting flange 104 into 1 the: pump inlet, ports 40 and "42 in the 13 :The bafiie 20-; is :arcuate in;shapazandrhaszan angular or "L '..sh'aped rcross-isectionT-hevtwo bolt holes :lv l8 arefadapted ito accommodate bolts 84 whereby-.isaidxboltsl'rigidly Ia'ster'nbothrthe filter X22v andtithe baffle 20 .lt0 .the.1 body- 3| The vertical armlal201of the. L shapedubafile plateiis *positioired at right anglesto theaxisfnfthetank .or-return passages .1222 .ahd I 23, 113111155 interrupt- .1 ing-'thezdirectionrofi.flowiotithe return fluid. lrhe other leg I24 of the L shaped bafl'le is concentric :lwithTthe ifixed .pressure 'el'iead i3 2. and ringfi Hiand .."l0,;.thus' ;'fo.rming a passag'e 126. at right. angles to. the itank-"passages 122. and 41.23."... .FIherefore,

new from passagez fl 2 and .l 23: .toyinlet" ports. All

and 42, but is interrupted in its directionroflfiow ...in order to iremoveany; air'suspendedj'n'. theiifluid and thereby prevent: cavitation.

:IA reliefyvalve 1.28 is lodatedinrthe;body:coun

.;: terbore .1130 of-passage t3 Z-zwhich': communicates iwitht pressurei chamber 48. .by meansiofapas'sages 1134;. I38, 811C141 54:12" The. relief. walvei structure comprises axdra-Wn' .metal cylindrical; bodyl'lili38 provided with '.an;;inward1y'projecting. flange 1110 at its outer .end. Anexternal r. flange ;.l42;is provided: for. fasteninghtheyalve;L281toi the body [9 by .means of machine iscrews. .-l44.u fllherirelief ..valve is a packaged.article and includes one-or more spring tensionsadjustment spacer washers M6 at theflfianged endfof theib'ody. A bushing l48 at theopen end isiadapted to fit vsnuglyzin counterborelfifi; iThe bushing-Ami! .functionsL-fas a valve seat to. supportithe'ldall fvalve" 150 :v'vhich I hold a torusshaped seal 158.

1 sure fluid will be dischargedthrough the internal directly into the tanlr l B; For simplicity of design and economicalreasons,- the passages'in"body l0 'are sho'wn to-be straight bored and approximately perpendicular to the external 'surface 5 in which they terininate. -By providing parallel as ages, they maybe constructed by multiple-spindle drills l and :the expense of a coring operationis 'thus eliminated.

'-' Asillustrated in Figure 4', tank'passa'ge's' H52, l 64,

. 6 "55,457, 168 and: pressure passages: Hg

and I36 are parallel and perpendicular to mount- 'lng surface? I12.

Motor passages I'M andl16 1in'the body lij extend to external connections" llB and [80; re- .spectively, from the valve boref280. flliguresilZ and'lfi illustrate a single acting. ya1ve..control1 ing asihgle acting. motor .184 ,by. means'of conduit .5 A cover plate I88 is adaptedv to fit mountingsur- .face I12 of body I 0. and be;retained thereoniby I boltsthrough boltholes. gover mel 88li s,;pro-

. vided with slots 191i .and';l 92 for.;cross.- connecting tank passages I64; and l 66. to ape ages .1: wand ;.hQ i v rr a e 1 ;inwplas sonth y v:10. am

are adapted to pass through bolt holes I66 and bottom in tapped holes I91 in body I6.

Figures 1 to 16 inclusive illustrate the power pack employing a double acting directional valve I2 located in thebody I6. The mounting surface I12 is designed to receive cover plate I88 or a second valve body. Figures 11 to 16 inclusive illustrate the power pack employing a second directional valve I68 mounted in the auxiliary valve body 266.

Passages 262, 264, 266, 266, 2I6, and 2I2 in valve body 266 are in line with passages I62, I16, I64, I36, I66, and I68, respectively, of body I6, and perform similar functions in the second valve body 266. Tank passages 2M and 2I6 in valve body 266 coincide with passages I65 and I61 in the body I6.

Slot 2I8 in the base of valve body 266 forms an intercommunication between passage I64 in body I6 and passage 264 in valve body 266. Slot 226 in body 266 forms a cross-connection between tank passages I66 and I61 in body I6 and H6 and 2 I6 in valve body 266. Two cylinder passages 222 and 224 are provided in the second valve body 266 and communicate with external connections 226 and 228, respectively, in the valve body 266.

The top surface 236 of valve body 266 is also a mounting surface adapted to receive the standard cover plate I88 or a third valve body (not shown). In Figures 11 to 16, the same cover plate I86 is mounted on surface 236 as shown in the single valve power pack (Figures 1 to 10). However, the hold down bolts 232 must be longer than the bolts I94 in order that they will pass through bolt holes 234 in valve body 266 to bottom in the tapped holes I91 of the main body I6.

As illustrated in Figures 12 and 16, the second directional valve I98 is a double-acting valve adapted to control the double-acting piston motor 236 which is connected by conduits 268 and 246 to external connections 226 and 228, respectively. The primary or lower directional valve 242 is a single acting valve in which case the external connection I18 is plugged. The surface entrance to other drilled inter-communicating passages such as I34 and I16 are blocked by plugs 244 and 246, respectively.

The directional valve I2 (Figure 4) is similar in form to the double-acting valve I96 in Figure 12. The single-acting valve 242 (Figure 12) is of slightly different construction from the doubleacting valve I98 as is evident from Figure 12. The lands 248 and 256 and the annular grooves 252 and 254 of valve I98 are similar to the lands 256 and 258 and the annular grooves 266 and 262 of valve 242. At the left end of the valves, lands 264 and 266 ofvalves I98 and 242, respectively, are similar. However, land 268 of valve I86 is wider than land 216 of valve 242 and annular groove 212 of valve 242 is wider than groove 214 of valve I98. External connection I18 of passage I14 is blocked by a plug 215 (Figure 16).

Caps 216 and 218 are provided for sealing the opening to valve recesses 286 and 282, respectively. In the counterbores 284 and 286 of valve recesses 286 and 262, respectively, oil seals 281 similar in design to seal 64 are employed on the valve stem. A centering spring 288 is located between two stops 286 and 292, respectively, for maintaining the valve in its central unloaded position as illustrated in Figure 4. At the end of each valve stem a detent hole 264, 266, or 268 is provided for coupling to a control or operating device (not shown).

The end chambers 366 and 362 in recesses 286 8 passages I62 and 262, and communicate with the tank I6 through passage 364 (Figure 1). Similarly, the enclosures 36I at the opposite ends of the valves are interconnected by passages I68 and 2 l2 to passage 366 which runs directly to tank I6.

Means for draining tank I6 is provided in the body I6. It consists of a passage 368 open to tank and connected by passage 3I6 to the external threaded connection 3 I 2 provided with a pipe plug 3I4.

The single-acting motor I84 is provided with a piston 3I6 adapted to lift a gravity load (not shown) by means of rod 3I8. The gravity load is capable of returning the piston to its lower position when conduit I86 is connected to tank. The double-acting motor 236 is provided with a piston 326 and through rod 322 which may be connected to a load requiring power to operate it in both directions.

Double-acting directional valve I2 of Figure 4 is provided with lands 324, 326, 328, and 336 and with annular grooves 332, 334, and 336 similar to the double-acting valve I96, the valve occupying the top position in Figure 12.

In operation, hydraulic fluid, preferably oil because of its lubricating characteristics, is supplied to the tank I6 through the combination filler-breather cap 24. After the transmission has been operated to b assured that all the units are filled, the fluid level in the tank I6 should be raised to a point above the upper inlet port 46.

As the shaft 36 and the pump rotor 26 are rotated, hydraulic fluid is drawn through the screen I62 and the inlet ports 46 and 42 into the expanding work chambers 44. The fluid is carried through 96 of rotation of the rotor 26 and is then discharged by th contracting work chamber 44 into the outlet ports 56 and 52 in the floating head 34 which lead to the pressure chamber 48.

In Figures 1 and 4, the power pack is illustrated employing only one directional valve I2. Multiple valve operation will be described in relation to Figures 12 and 16.

Directional valve I2 is a double-acting valve adapted to control a double-acting work cylinder or motor and indicated .by numeral 236 in Figure 16. In the valves neutral position (as shown in Figure i), the pump I4 is unloaded to tank I8 via passages 54, I36, I34, I16, groove 332, passage I64, slot I66, passages I65 and I22 to tank.

When directional valve I2 is shifted to the right (Figure 4) land 324 blocks unloading passage I16 and causes a pressure build-up in pressure passage I36. The shifting of valve I2 to the right connects passages I36 and I16 by means of annular groove 334 and thus direc.s operating pressure fluid to one end of the double-acting motor. At the same time, annular groove 332 connects tank passage I64 to cylinder passage I14, thus permitting the discharge of exhaust fluid from the other end of the motor to tank.

When the motor operation is complete, merely releasing the operating handle (not shown) of Valve I2 will permit the valve to return automatically to its neutral or unloading position under the force of centering spring 288.

By shifting directional valve I2 to the left, the unloading passage I64, normally in communication with passage I16 by means of annular groove 332 in its neutral position, is blocked by land 326. In the same operation, pressure passag I36 is connected to cylinder passage I14 by means of groove 334, and cylinder passage I16 is exhausted by means of annular grooves 336, passage I66, slot and 282, respectively, are interconnected by tank I92, passages I61 and I23 to tank I6.

.Asirspbintedl out? ,:abo ve, qchamberwfli'i is? under its'neutr'al position and-zunload thepump via; pasr; pressure:whemthe: wnp is operat d,.,since;1its sages I34 and I1-[l,-,annu1argr00ve212;;passage" formsapartgofthe chainofpumproutlet passagesn I64; slot22I8,-=passage2204,:annulargroove 214 jof The; floating-pre sure .ahead {.34 qjsz urgedagainstvalve @I98,-passage 266,-slot jI90',vand passages 2M; the ringl' 3ll andthe -rotor:- 26 with aliorce; vary 5 I65",-and.I22 .to-tank., Byshifting valve 2% to its,,- ing j in' :uproportion;tor thes operating pressure. 1 extreme 1eft,;position;,cylinderi passage-r: I16 1 Therefore; the .bearingyseal between: the fioating i opened to tank by means of annular; groove. 262;: head- 34, and the; ring-30.-;and;rotor 126 willnbe passage I66,:s1ot220,-*and "passagesq m'lf and I23 i jmIieased-or-decreasedaccording-to the pressureto tank (Figure 11'). Passage ;;I14'1andaits eX demandr. 4 v, p, A r o .10 ternalcylinder connection I'lW are-lolocked by? ;Any oil-lea age in athe valve recess-"zflfl beyondg plug;215: t r I r the-landfi would normallybe1 -pocketed-in:1 .If;;doubleactingvalve l98:is shifted in either chamber 300vand interfere with valve operation, direction,.itsoperation'is.similarpto the function by; causing ga dashpotnaction; I-Iotvever,1 drain ing of valve; I2 as described above; .Whenbothi passage I 62and 3.9.4 connectmhambenflllldirectly. z 15 valves are moved to, the right, operating pressure to etank Y In the rsamejmannenf; the lright end fluidwiltbe "directed :through .cylinder passage chamberBU L togthe rightof land 330-isv drained llfil'andz22d torthe respective motors. Discharge by" pas sages I63- and. 305,-toetank s; I, fluid: fromwthe other-:endof motor"236ywill be. With the valve I2 in either operating positiondirected-to tank =I6 via'xcylinder passage 222;: ane wherehv-pressure isloloclged in theunloading nular groove :2-T4ypassage 206; slot ISILandpa's' passage; pressure-fluidavill eontinue to flow to the: sagesr2l'4, Island: I22; V v motor until the load pistonfhasflreaclfledits-limit To reverse'the direction of trave1of'the"mot0rs 5 oftr aveln The system willthereafterhe relieved I84 and 236', valves242 and I98must be shifted.- oiiexcesspressure hy-imeansofirelief valve 128.,- tosthe'ext'reme left'IFig'ure 12) When valve I38 i 'I'nebperating pressure assage'uai connected '25is shifted-to thelleftt'of its'neutraliposition, land bytpassages I34 and.I32-togballvalvell50,. When 268 blocks unloading passage v2!'I6,'and cylinder pl lil f 0 aeainst. the valve '-I 5I J exceeds 7 passage 222 is connected "tolpressure passage13fi the 'tension-inispring I521;theTbal'lgwillQbe'Jifted1 bymeans ofannular groove"252. Cylinder pas-2- and-gexcess pressurelfiuid-jrelieved:through .Ioore sage 224 of valve' I98'in its left position-"is OOH-3' i seem orifice g: 6 I .-of the valve body; I3 8 to tank. neotedtoitankrl 6 via annular groove 2 54,-passage Returnfluid, "either fr'on fthe-hdischargeside oi 2 III; slot 'I92,"passages 2I 6,'-I.6I,and I23. Cylin-- v theimo'tor unis .unloadi'ng'jpa'ssageenters; the}. der ipassa'gal'lfi 'of valve-142 in its left position" I6. ,throughipassages-{2210i I23'fl Dirringl is-connected: to tank by ann'ular gr0ove22; pasoperation, diseliargev'fluid,may begfilledgvvithlair sageslfifi; slot:22fl',;and:passages I61 and I 23'. bubbleslbutllthelbaiii" :2a mterruptsmmgid rece It;wi1'l:thus:be'seen that the present inventionw tion of flowan'd allo v heg'air toseparateifrbmu hasnprovided'a-power-pack-of simple, compact, the liquid.,..As the flf- 1d;1eav s"pa ag s;|22 'and and economical design and. suitable for operat- I23 'itlmustwfiojwgbr divide theiightand left ing1qandcontrolling;.;one or more :fluid motors.-

' f V V j v. 'tthefbafiijeland II This' is accomplished-by providinga;pump,'tank,1,, heta' nk lfi m nesirecmo m rmmtneeo and control-gvalve-assembly=construeted into-ax: 22 and follow an'indirect path to'tlie'screeii unitary structure and adapted -'for mounting ad- 1 H I v H q ditionalnvalve -units as anintegral'part of-the 'Ilj eilarge;prossgseetionlof the hafliepassagefflfi basic=structure.- I v V 1 furthermoreredu'cesthe'veloo ypfjtlfereturningl- VCertain ifeature's-of =th'e pump construction oil' l'oefo're'it reachesthe main-bodyfofoilfin the lizwh-ich arewdisclosed but not 'claimed herein are"; tank and thus causes very little churning up of the; subject I matter a of and are .being :claimed in theoil inthe'tai'ikif" the application of Duncan B.- Gardiner eta1., Se- Wlinmoretha'r'i one'loa'd device'er meters to ria1?N0-..'-720,142; "entitled Powertransmissiomand be oper'atedg such as? is 'illustrate'd -'in:' Figure 416,1" filed-:on-Januaryi 4,1947; v v v v multipleiidirectional valves 'iimust *tbe iemployed: Y -1 Certain features of the 'directionalcontrol valve Motori-lfldahasiiaz-singleziacting. piston "3I5- con-z" body;,:c0nstruction which are disclosedbut not a trolled iby valve flz-gandsis raised' by means. of: claimed herein are the subject matter of andare hydraulic fluid entering the=-cylinder--through being'claimedin'the appl-icationof Ferris T. Har-' conduittIBQuThedoulole-acting:moton-236 isconringtonwet-alr, SerialNo; 168,312, entitled Power trolled by-,valve-;I98 (Figure-J2); Int'order .to.55 -Transmis sion 'and -fi1ed:.June:-'15-, 1950. I convert the powerpackunit of, Figure. .4 intolal While the form of embodiment of the inventionmultiplem'otor andyalve,controlgunit thehover.Q as z hereinadisclosedconstitutes a preferred form-,-- platel lta "is raised; ,Anhindividualjorauxiliary}:v itlis tobeunderstood-that other forms-might be valve hodyv 26.01 is then, mou'nted on surfaceQ I 12, 'j adopted-Fall coming wthin the scope of theclaimsmplacelof memsawhicn iniit rgh. .is veq I 1 I v tofmountinglsurfaee'23'0; of the auxiliaryvalvel What; is claimedis as follovvs'se. q bddy,v 200,: oloviouslvflanyjnumber of additional L A hydraulicpump-i-ncluding-a cam ring: envalve bodies 200 inay" be'added "in"th'is' fashion-i circlingaa*rotor-provided avith'vanespositioned fi yb aes'irdl" A I between pump heads to form working chambers,-; Ifji't is desiredtp b erateehe single "actin"g"mo'-"' 6 diametrically opposed inlet ports- 'in onewpump tor*'-3 I fifivalve 242 (Figure 12) is*s'hiftedi to the head and-outlet: ports in the other pumphead,- i right" until larid' '26'6 blocks. unlo'ading ipassage the DOItS'eil'l one'head'being angular-1y displaced I10. I operating pressure :fluid' will be' directed F air-90? from the other ports, dowel means for -alin-;- from pressure essagenss 'toscylindergIpassager ingthelinlet andputlet-ports ofthe pump-heads I16by.meansofannulan:groovezzzfio oflvalve 242r; v with the camring', thedowel means inthe ring- When'piston- Slfifoffinoton .I8A:has:beenrraised;:' beingsymmetricalwithrespect to an imaginary tozits top-limit, excessz pressiure; fluid {will :be re planer angularlylidisplaced' from the 'majoraxis lieved to tankzj 6" :by. means-.of; relief-valve I28 Ofith cam;ellipse by anangle-of 45-whereby the v B areleasingvthei-op ratin ihandlexforzzvalve;242;; rotorand eam ring -may berturned overw d f -1 the"-centering-spring:j288=twillireturn-zithe'svalve' toe: end to provide forcorrect positioning of the rotor and ring in relation to the inlet and outlet ports for reverse rotation of the pump.

2. A hydraulic pump wherein the pump includes inlet and outlet ports, a cam ring of approximate elliptical form and rotary pumping elements cooperating with said ring and ports to withdraw fluid from the inlet port and expel fluid to the outlet port, and locating means on the ring symmetrically positioned with respect to an imaginary plane angularly displaced from the major axis of the cam ellipse by an angle of 45 whereby the cam ring may be turned over, end for end to provide for correct positioning of the ring in relation to the inlet and outlet ports for reverse rotation of the pumping elements.

3. In a hydraulic pump unit including inlet and outlet ports, an elliptically shaped cam ring and rotary pumping elements cooperating with said ring and ports to withdraw fluid from the inlet port and expel fluid to the outlet port, means for locating the cam ring in relation to the inlet and outlet ports of the pump including dowel means in the ring, said dowel means being angularly displaced 45 from the major axis of the cam ellipse whereby the cam ring may be revolved end for end to diametrically interchange the dowel means position and angularly displace the cam ring for correcting the cyclic operation when the pump rotation is reversed.

4. A hydraulic pump comprising a body element, a cam ring encircling a rotor provided with vanes positioned between an axially shiftable pump head and a fixed pump head to form working chambers, a recess in the body element adapted to receive the shiftable pump head and position it adjacent the rotor, arcuate outlet ports extending axially through the shiftable head to connect the working chambers and recess thereby maintaining the recess under operational pressure for moving the shiftable pump head axially into sealing contact with the rotor and ring with a force varying in proportion to the pump operating pressure, arcuate inlet ports extending axially through the fixed head to provide direct passages to the working chambers, and a drive shaft connected to the rotor and extending outside the body on the side of the rotor containing the recess.

5. A hydraulic pump comprising a body element, a cam ring encircling a rotor provided with vanes positioned between an axially shiftable pump head and a fixed pump head to form working chambers, a recess in the body element adapted to receive the shiftable pump head and position it adjacent the rotor, pressure passages for maintaining the recess under operational pressure and moving the shiftable pump head axially into sealing contact with the rotor and ring with a force varying in proportion to the pump operating pressure, an open-end tank element attached to the body so as to enclose the pump, the body element functioning as a cover for the open end of the tank element, and arcuate inlet ports extending axially through the fixed head directly to the tank enclosure.

6. A hydraulic power pack unit comprising a body housing a pump and a directional valve therein for controlling a fluid utilizing device, a mounting surface on the housing, a plurality of passages extending from the directional control valve to the mounting surface, a second valve body attached to the mounting surface for controlling a second fluid utilizing device, a plurality of passages extending throngh the second valve body and contiguous with the passages in the body housing.

7. A hydraulic power pack unit comprising a body housing a vane type pump and a directional valve therein for controlling a fluid utilizing device, a vane rotor and cam ring mounted in the pump, a recess in the housing adjacent the vane rotor and cam ring, a pressure plate located in the recess free to move axially into bearing and sealing contact with the rotor and ring, a pressure passage connecting the pump outlet to the recess whereby the recess is maintained under operating pressure for urging the pressure plate toward the rotor and ring with a force varying in proportion to the operating pressure of the pump, a mounting surface on the housing adapted to receive either a cover-plate or a second valve body on said surface for controlling a second fluid utilizing device, and a plurality of passages extending from the directional control valve to the mounting surface.

8. A hydraulic power pack unit comprising a body housing a pump and a directional valve therein for controlling a fluid utilizing device, said pump being mounted in one sideof the body and including a shaft connected thereto and extending from the opposite side of the body, said body being so formed that the pump shaft and directional valve are mounted therein with the axis of the directional valve being perpendicular to the axis of the pump shaft, a mounting surface on the housing, a plurality of passages extending from the directional control valve to the mounting surface, a second valve body attached to the mounting surface. for controlling a second fluid utilizing device, a plurality of passages extending through the second valve body and contiguous with the passages in the body housing.

9. A hydraulic power pack unit comprising a body housing a. rotary vane pump and a directional valve therein for controlling a fluid utilizing device, said body on one side thereof including a fixed pressure head and a cam ring forming .a pump working chamber, the pump being mounted in the pumping chamber and having a shaft connected thereto extending from the opposite side of the body, a mounting surface on the housing, a plurality of passages extending from the directional control valve to the mounting surface, a second valve body attached to the mounting surface for controlling a second fluid utilizing device, a plurality of passages extending through the second valve body and contiguous with the passages in the body housing.

10. 'A hydraulic power pack unit comprising a body housing a pump and a directional valve therein for controlling a fluid utilizing device, a mounting surface on the housing, for receiving either a cover plate or a second valve body, a plurality of passages extending from the directional control valve to the mounting surface, a second valve body removably attached to the mounting surface for controlling a second fluid utilizing device, a mounting surface on the second valve body for receiving a cover plate, a plurality of passages extending through the second valve body to the mounting surface thereof and contiguous with the passages in the body housing, a cover plate removably attached to the mounting surface of the second valve body and attachable to the mounting surface of the housing, and passages in the cover plate cooperating with the passages extending to the mounting surface of the second valve body and also adapted to coopcrate with the passages of the housing extending to the mounting surface thereof when the second valve body is removed from the housing.

FERRIS T. HARRINGTON. JOSEPH A. MARTIN.

GORDON R. ELLIOTT. LESLIE W. HAISEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Neuls Apr. 17, 1928 Number g5 Number 14 Name Date Hobson May 23, 1933 Vickers Feb. 5, 1935 De Millar Oct. 13, 1936 Centervall Dec. 27, 1938 Anthony et a1 Feb. 7, 1939 Williams Jan. 9, 1940 Day Aug. 6, 1940 Twyman June 24, 1941 Twyman June 24, 1941 Vickers Mar. 27, 1942 Kvavle et a1 Aug. 25, 1942 Kellett Nov. 3, 1942 Curtis et a1 Oct. 31, 1944 Stephens Nov. 14, 1944 Curtis et a1 Feb. 13, 1945 Curtis Feb. 13, 1945 Baldwin et a1. Sept. 11, 1945 Curtis et al Feb. 5, 1946 Pfost Mar. 19, 1946 Parker et al. Feb. 4, 1947 Hawkins et a1. May 4, 1948 FOREIGN PATENTS 7 Country Date Great Britain May 12, 1910 

